Patients with symptomatic mild to moderate bilateral knee osteoarthritis will be candidates for this pilot study. Baseline data includes radiographs, MRI imaging, clinical data on knee pain and analysis of synovial fluid inflammatory markers. Bone marrow will be aspirated from the patient's iliac crests and the cellular rich portion will be concentrated. Randomly, one knee will be injected with the bone marrow concentrate. The contralateral knee will be injected with only sterile saline for placebo. Follow-up analysis of synovial fluid will be at one week and 6 months after injection; clinical data will be obtained at 3, 6 and 12 months and MRI imaging will be performed at 6 months after injection, with repeat radiographs at 12 months